RIGA German Greenhouses - Exaco

• Because: for one thing the experts don’t call all covered garden structures
greenhouses, as is currently the case in our country. But in Europe where the
greenhouse concept was invented over 100 years ago, they consider any structure
using less than 8 mm twin-wall polycarbonate not a proper greenhouse but a
“season-extender”.
What is a “Season Extender”?
• It is a structure covering flowers and plants designed to prevent a late frost from
damaging the flowers and plants. They are too expensive, relatively speaking, or
sometimes impossible, to keep warm enough (above 50ºF) during day time frost.
• These structures usually include all “greenhouses” which use 5 mm or less twinwall
polycarbonate glazing. Or use only single layers of heavy polyvinyl
sheeting, or 3 mm or less single layered glass.
• To keep these warm enough in the middle of the winter you need so much heat
that often the plants near the heating unit are damaged from too much heat.
• The cost of heating these units properly is too high; in the long run it is cheaper
to buy a better-insulated greenhouse.
What is a (proper) greenhouse?
• Usually, a structure which uses at least 4 mm glass or better still at least 8 mm
twin-wall polycarbonate glazing. These units are designed to be used in cold
weather – including continuous day-time frost conditions
• A unit designed to be kept comfortable (about 50-53ºF) during the middle of the
winter with out costing an arm and a leg to do so.
• Less insulation can mean significantly higher heating costs.
Why use twin-wall polycarbonate instead of glass?
• In the old days twin-wall polycarbonate glazing did not exist and therefore all
older greenhouses have only glass or a corrugated plastic type walls.
• Cheap glass was/is cheaper than good polycarbonate
• Since the invention of the twin-wall polycarbonate glazing it has become the new
material to use – even the professional growers are using it now.
• Twin-wall polycarbonate glazing is much more efficient – like a double pane
window it provides much better insulation.
• At least 40% cheaper to heat – for a same size greenhouse with 4 mm single
layered glass or less.
• Twin-wall polycarbonate glazing defuses direct sunlight – glass does not. This is
important to sensitive plants.
• Provides much better UV protection
• Easier to handle – not dangerous
• Easier to assemble – safer and lighter
• Safer for children and pets
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